1. Field of the Invention
The invention relates to tortillas and other baked, unfermented dough products in generally flat form that are stacked within a package.
2. Background Information
1. The Prior Art Product
Although it is believed the invention is applicable generally to unfermented cooked dough products with a textured surface layer in a flat shape, including pitas, pancakes, matzos and the like, the invention was made with tortillas and will be described with respect to such tortillas.
Unlike the usual dough breads with yeast, dough in unfermented cooked dough products, such as a tortilla, does not rise but when the product is baked quickly at high heats, the dough puffs to a varying degree, either from steam formed within the product alone, or from steam and baking powder, an ingredient. The steam condenses into moisture when the tortilla is cooled. This moisture is trapped within the tortilla interior, but eventually the tortilla, if not consumed, will dry out.
Baking time is relatively quick with, for instance tortillas, usually taking from 15 to 40 seconds. The temperature of the tortilla may be 180.degree. F. when it comes out of the baking phase. It may then be rapidly cooled at, for instance, a temperature in the range of 30.degree. F. to 50.degree. F., or at an ambient temperature of, for instance, 78.degree. F.
The tortilla, immediately after baking and cooling, is relatively soft and flexible, and has a textured, contoured, distinct surface layer which has been exposed in the baking process to high heat from, for instance, ribbon gas burners. Contour on the surface layer exists on a very small scale but even to the naked eye, such surface is almost a "moonscape" with creases, ridges, undulations, swirls, depressions, folds, and other contours formed by the non-uniform expansion of the steam during the baking process, as well as from the effect of the high heat.
The tortilla outer distinct surface layer, during baking, is directly exposed to the heat. As opposed, for instance, to a crust on bread, the distinct surface layer is highly flexible and formed into the distinct layer by the relatively rapid baking at high heat and the cooling process. The moisture in the uncooked dough "puffs" during baking and "blows" against the outer surface which has been quickly baked since it is directly exposed to the high heat, causing somewhat of a light "balloon" effect, with the outer surface of the tortilla forming a "skin" of the balloon.
Such tortillas made of corn or wheat flour are well known and extensively made and consumed.
The tortillas, after baking and cooling, are often stacked, one on top of another, and then sealed in a package.
2) The Prior Art Methods
Historically, tortillas were made by the home cook by preparing the dough, forming the tortilla blank in the form of a thin flat disk of about 6" in diameter, by hand or with a stone roller, and baking the tortilla on a flat hot surface such as a stone or metal plate, and then consumed.
Traditionally, the dough was made of a corn flour, but more recently wheat flour tortillas have become popular.
Also, in recent years, tortillas are increasingly being "factory made" on high speed machinery and then packaged in vertical stacks in moisture-proof, sealed packages made of a plastic such as polyethylene.
Typical commercial production rates per installation can range in output from 1200 dozen per hour for 6" tortillas to 600 dozen for 101/2" tortillas. The tortillas can be either manually or automatically stacked into, for instance, stacks of one dozen each. A popular size factory-made tortilla is about 101/2" in diameter, weighs about 73 grams, and is from about 0.060" to 0.090" thick.
The packages of stacked, fully baked tortillas are subsequently either kept at room temperature, refrigerated, or frozen until consumed. The mode of storage determines the possible permissible time the product can be kept in an edible state.
When intended for use, the package is opened and the tortillas separated and consumed. The tortilla is fully cooked, but is generally warmed or further processed into, for instance, tacos.
The invention is independent of the means and methods of baking, cooking, and stacking the tortillas. It works with all such means and methods, and does not slow down any of such means and methods.
3. The Current Problem
In packaging the tortillas, which can be, as indicated, from for instance 4" to 14" in diameter and from, for instance, 0.030" to 0.200" thick, the tortillas are stacked vertically, one on top of another. A typical stack has 12 tortillas.
The tortillas, which are stacked automatically or by hand, are placed in moisture-proof packages such as polyethylene, and sealed.
When intended to be used, the package is opened and the tortillas separated, one from the other. It has been found that the textured, distinct, outer layer of the tortillas, particularly those of wheat flour dough made by the hot press method, stick and adhere or bond to one another and when separated, cause the distinct surface layer to be peeled from the tortilla, resulting in an unsightly, damaged and defective product. In other instances, the sticking causes the tortilla to break and tear apart.
The present invention overcomes the problem in a simple and effective way, without altering the appearance, texture, taste, flexibility, or other characteristics of the tortilla.
4. Related Prior Art
In the preparation of cooked dough products, sticking has traditionally been a problem, but this problem has been virtually always with the dough prior to cooking. The uncooked dough, as any baker, either home or commercial, can attest, sticks to pans, mixing bowls, utensils and other dough. The solution has been simple; namely, a generous use of loose dusting flour, freely sprinkled in clumps, over the product and then generally rubbed over and into the surface, or in a bulk blanket under the product. Much of the flour remains loose on the surface of the dough and acts as a dry lubricant. The surface is not a distinct layer, but is simply the exposed portion of the mass, and is not affected by relatively rough treatment and cannot in effect be torn. The powder that adheres to the dough is simply baked into the surface of the dough during the baking operation and, as for instance in bread, contributes to a crust.
In the commercial preparation of tortillas, loose dusting flour in bulk blanket or freely sprinkled clump form also was and is often used on the uncooked dough to prevent sticking, particularly in the die-cut method wherein an extruded sheet of dough with much dusting powder in free form thereon is die cut in the fashion of a "cookie cutter", to form the tortilla blank which is then baked. The uncooked dough can be handled roughly, and has no skin or outer layer. The dusting flour can be rubbed over the surface and spread without injury to the dough. The leftover sheet is again extruded, with the dusting powder mixed in. As set forth in U.S. Pat. No. 4,938,126, which describes various commercial methods of preparing tortillas, such use of dusting flour is objectionable since it results in a baked tortilla that has a relatively tough surface layer, whereas it is desirable to have a relatively finer surface layer on the finished tortilla.
In the hand-stretching method of commercially prepared tortillas wherein at a certain stage of preparation, the tortilla dough is stretched by hand, much use of dusting flour in loose, bulk, or clump form is again made on the uncooked dough wherein, again, a relatively rough-textured surface layer results.
In applying dusting flour to the uncooked dough, generous amounts are freely and loosely sprinkled, in bulk or clump form, over the dough. In many instances, the flour is then rubbed over and into the dough by hand. The dough surface is insensitive to such treatment, so the dough can be handled vigorously without a problem. Where the dough is of a more delicate nature, such as in pie crust, of course more care must be taken in handling the dough.
In the quest for an improved commercially prepared tortilla, use is now being made of a so-called "hot press" method as set forth in the above-mentioned United States Patent. Such method uses heated platens which flatten a dough ball into a thin, flat disk which is baked to form the finished tortilla. The heated platen substantially reduced the problem of dough sticking or adhering to the equipment, so that virtually no dusting flour on the uncooked dough to prevent such sticking is needed. The process results, particularly with the wheat flour tortillas, in a more fine-textured, separate outer layer which is much desired in the finished product. However, wheat flour tortillas produced by the hot press method particularly tend to stick together when stacked in a package.
Prior efforts have been made to reduce the effects of sticking of tortillas, as well as other cooked dough products in flat disk form such as pancakes, pita, and the like, one to another, in a stack contained in a package. An example of such efforts is set forth in U.S. Pat. No. 4,993,788. It was recognized there that the internal moisture within the tortilla appeared to have some relation to sticking. By permitting the tortilla to cool individually at room temperature, on a long travel, after baking and with much cooling air, the stack sticking problem was approached. Such an approach requires much space and much time added to the total process, and is generally unsatisfactory.
Numerous other efforts have been made to prevent such sticking, including trying to form a crust or the like on the tortilla, but these have not proven fully satisfactory.
Additionally, there has been coating tried which includes for instance an oil or the like but, again, this changes the taste and texture of the tortilla, and also the appearance.
Paper separators between the stacked tortillas have been used. This method is expensive, and the packaging time is greatly extended in order to place the paper.